Active matrix driving display device and image displaying method using the same

ABSTRACT

LCD device includes two substrates, a first and second color filters, two liquid crystal layers. The first color filters are formed on portions of the second substrate corresponding to border area The second color filters are formed on portions of the second substrate corresponding to the display area except the border area. A first liquid crystal layer between the first and the second substrate is comprised in border area, and a zero electric field is formed on the first liquid crystal layer so as to completely transmit light incident into the first liquid crystal layer therethrough. A borderline having various colors can be displayed by forming various patterns of color filters having various colors on portions of the second substrate corresponding to the border area under normally white mode, thereby producing picture frame effect while images are displayed on the screen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/016,416 filed on Jan. 28, 2011, now U.S. Pat. No. 8,218,112 which isa Continuation of application of U.S. patent application Ser. No.10/526,689, filed on Mar. 3, 2005, now U.S. Pat. No. 7,894,021 whichclaims priority under 35 U.S.C. §119 to Korean Patent ApplicationNumber: 2002-53635, filed on Sep. 5, 2002, and under 35 U.S.C. §365 toInternational Patent Application Number: PCT/KR2003/001719, filed onAug. 26, 2003, the contents of which are incorporated by referenceherein in their entirety.

TECHNICAL FIELD

The disclosure relates to an active matrix display device and imagedisplaying method using the same, and more particularly to an activematrix display device for displaying a borderline on a display screenthereof and image displaying method using the same.

BACKGROUND ART

Recently, there is an increased requirement for a flat panel displaydevice that can be manufactured in a thin and light structure having alow power consumption compared with a CRT type display device, such as aliquid crystal display (LCD) device, an organic electroluminescentdisplay device, plasma display panel (PDP), etc. Especially, the LCDdevice is a popular display device for which there is a rapidlyincreased demand in the world.

The LCD device can be classified into an active matrix driving displaydevice and a passive matrix driving display device in aspects of drivingmethod. The active matrix driving display device is driven by usingswitching devices, such as thin film transistors, and twisted nematicliquid crystal, and the passive matrix driving display device is drivenby using super twisted nematic liquid crystal.

The active matrix driving display device requires another drivingcircuits in order to drive the switching devices. The active matrixdriving display device can be applied to the LCD device and the organicelectroluminescent display device. However, since the passive matrixdriving display device does not use the switching devices such as thethin film transistors, the passive matrix driving display device doesnot require another driving circuits to drive the switching devices.

In the active matrix driving display device, characters, figures, imagessuch as still images and moving pictures are displayed on a display areaof the display device. Recently, there are requirements for a displaydevice for displaying a borderline, to thereby produce neat screeneffect and a picture frame effect while images are displayed on thedisplay area of the display device.

The conventional active matrix driving display device requires anotherdriving circuits for generating signals corresponding to the borderlineor should change existing driving circuits in order to display theborderline having a predetermined color.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention is provided to substantially obviateone or more problems due to limitations and disadvantages of the relatedart.

It is a first object of the present invention to provide an activematrix driving display device for displaying a borderline having apredetermined color without using another driving circuits and withoutchanging existing driving circuits thereof.

It is a second object of the invention to provide an image displayingmethod where a borderline having a predetermined color can be displayed.

To accomplish the first object of the invention, there is provided aliquid crystal display device comprising: a first substrate; a secondsubstrate being opposite to the first substrate; a first color filterformed on a first portion of the second substrate, the first portioncorresponding to a first area of a display area, the first area being aborder area of the display area; a second color filter formed on asecond portion of the second substrate, the second portion correspondingto a second area of the display area, the second area being the displayarea except the border area; a first liquid crystal layer disposedbetween the first and the second substrate in the first area, and a zeroelectric field being formed on the first liquid crystal layer so as totransmit all of a light incident into the first liquid crystal layertherethrough; a second liquid crystal layer disposed between the firstand the second substrate in the second area.

In another aspect of the invention, there is provided an active matrixdriving display device comprising: a timing controller generating afirst dummy line data, a second dummy line data, a first dummy pixeldata and a second dummy pixel data, receiving a first display area datato generate a second display area data that is obtained by adding thefirst and second dummy pixel data to the first display area data, andgenerating a first control signal that allows the second display areadata and the second dummy line data to be outputted to each row of adisplay area having a plurality of rows and columns, the first dummyline data having a first color information for each pixel in a firstborder area corresponding to an upper borderline, the second dummy linedata having a second color information for each pixel in a second borderarea corresponding to a lower borderline opposite to the upperborderline, the first dummy pixel data having a third color informationfor each pixel in a third border area corresponding to a leftborderline, the second dummy pixel data having a fourth colorinformation for each pixel in a fourth border area corresponding to aright borderline, the first display area data having a fifth colorinformation for each pixel in the display area except the upper, lower,left and right borderline; a first driver generating a first dummy linedriving signal and a second dummy line driving signal base on the firstcontrol signal and generating a plurality of second control signals baseon the first control signal, the first dummy line driving signalallowing the first dummy line data to be displayed on the first borderarea, the second dummy line driving signal allowing the second displayarea data to be displayed in a row unit on the display area except theupper, lower, left and right borderline; a second driver receiving thefirst dummy line data, the second display area data and the second dummyline data from the timing controller and allowing the first dummy linedata, the second display area data and the second dummy line data to bedisplayed on the display area in response to the first dummy linedriving signal, the second control signals and the second dummy linedriving signal.

To accomplish the first object of the invention, there is provided animage displaying method comprising: providing a first liquid crystallayer disposed in a first area with a first light, the first area beinga border area of a display area, and a zero electric field being formedon the first liquid crystal layer; transmitting the first light throughthe first liquid crystal layer to provide a first color filter layer inthe first area with a second light, the second light being thetransmitted first light; transmitting the second light through the firstcolor filter layer to display a borderline in the first area, a color ofthe borderline depending on the color of the first color filter layer;providing a second area of the display area with a third light, thesecond area being the display area except the border area; transmittingthe third light through a second liquid crystal layer in the second areato provide a second color filter layer in the second area with a fourthlight, the fourth light being the transmitted third light; andtransmitting the fourth light through the second color filter layer tooutput an modulated light on the second area, a color of the modulatedlight depending on the color of the color filter layer.

In another aspect of the invention, there is provided an imagedisplaying method comprising: generating a first dummy line dataincluding a first color information for each pixel in a first borderarea of a display area having a plurality of rows and columns;generating a second dummy line data including a second color informationfor each pixel in a second border area opposite to the first borderarea; generating a first dummy pixel data including a third colorinformation for each pixel in a third border area, the third border areabeing perpendicular to the first border area and having a first width;generating a second dummy pixel data including a fourth colorinformation for each pixel in a fourth border area, the fourth borderarea being opposite to the third border area and having a second width;receiving first display area data to generate second display area datathat are obtained by adding the first dummy pixel data to the firstdisplay area data, the first display area data having a fifth colorinformation for each pixel in the display area except the first, second,third and fourth border area; generating a third display area data thatis obtained by adding the second dummy pixel data to the second displayarea data; and sequentially displaying the first dummy line data, thesecond display area data and the second dummy line data row-by-row onthe display area.

According to above present invention, the active matrix driving displaydevice can display a borderline having a color determined by a user'sfavorable color.

In addition, the active matrix driving display device can display aborderline having various colors by forming various patterns of colorfilters having various colors on portions of the second substratecorresponding to the borderline under normally white mode.

In addition, in the active matrix driving display device, the displayarea can be divided clearly into the borderline and an area where imagesare displayed by displaying the borderline on a screen of the activematrix driving display device, to thereby produce picture frame effectwhile images are displayed on the screen.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will become moreapparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings, in which:

FIG. 1 is a schematic block diagram showing an LCD device for displayinga borderline on a display screen of an LCD panel according to oneexemplary embodiment of the present invention;

FIG. 2 is a view showing a display screen of an LCD panel in which theborderline is being displayed by means of the LCD device of FIG. 1;

FIG. 3 is a view showing R.G.B. signals applied to the LCD panel so asto display the borderline by means of the LCD device of FIG. 1;

FIG. 4 is a view showing R.G.B. signals applied to the LCD panel througha source driver so as to display the borderline by means of the LCDdevice of FIG. 1;

FIGS. 5A, 5B and 5C are equivalent circuit diagrams showing a thin filmtransistor corresponding to the borderline of the LCD panel so as todisplay the borderline according to exemplary embodiments of the presentinvention;

FIGS. 6A, 6B and 6C are sectional views showing an LCD panel includingthe thin film transistor shown in FIGS. 5A, 5B and 5C;

FIG. 7 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a firstexemplary embodiment of the present invention;

FIG. 8 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a secondexemplary embodiment of the present invention;

FIG. 9 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a thirdexemplary embodiments of the present invention;

FIG. 10 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a fourthexemplary embodiments of the present invention; and

FIG. 11 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a fifthexemplary embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a schematic block diagram showing an LCD device for displayinga borderline on a display screen of an LCD panel according to oneexemplary embodiment of the present invention.

Referring to FIG. 1, the LCD device for displaying the borderlineincludes a central processing unit (CPU) 10, a graphic controller 20, atiming controller 30, a source driver 40, a gate driver 50 and an LCDpanel 60.

For example, a first RGB signal outputted from the CPU 10 is applied tothe graphic controller 20 and the timing controller 30, and borderlineinformation is added to the first RGB signal in the timing controller30. Then, the first RGB signal having the borderline information isapplied to the LCD panel 60 by the source driver 50 through a pluralityof data lines (D1, D2, . . . , Dm) at an appropriate timing. The RGBsignal includes red, green and blue color information.

The graphic controller 20 receives the first RGB signal from the CPU 10and generates a second RGB signal, Vsync, Hsync, DE (Data Enable) andMclk (Main Clock) signals to provide the timing controller 30 with thesecond RGB signal, Vsync, Hsync, DE and Mclk signals. The second RGBsignal an RGB signal having same color information as the first RGBsignal. The Vsync signal is a vertical synchronization signal thatidentifies a beginning point of each frame base on the first RGB signal.The Hsync signal is a horizontal synchronization signal that identifieseach line of each frame base on the first RGB signal. The DE signalmaintains a high level only during a period in which image data areoutputted, and the Mclk signal a main clock signal.

The timing controller 30 receives the second RGB signal, Hsync, Vsync,DE and Mclk signals and generates a source driving signal for drivingthe source driver 40 and a gate driving signal for driving the gatedriver 50. The source driving signal includes a LOAD, Hstart, RGB signalhaving the borderline information, and the gate driving signal includesa gate elk and Vstart signal.

The timing controller 30 generates a first dummy line signal and asecond dummy line signal. The first and the second dummy line signalhave information for the borderline corresponding to a first line and alast line of the display area, respectively. In addition, the timingcontroller 30 adds information for the borderline corresponding to aleft and right borderline of the display area into the received secondRGB signal and generates an RGB signal having borderline information.For example, borderline information may have RGB color informationcorresponding to borderlines such as a top, bottom, left and rightborderline.

The Hstart signal is a signal that indicates a beginning point of timewhen the RGB signal having the borderline information outputted from thetiming controller 30 is applied to the source driver 40. The sourcedriver 40 converts digital signals of the first dummy line signal, thesecond dummy line signal and the RGB signal having the borderlineinformation into analog signals. The analog signals of the first dummyline signal, the second dummy line signal and the RGB signal are appliedto the LCD panel 60 in response to the LOAD signal.

The first dummy line signal, the second dummy line signal and the RGBsignal are applied to the LCD panel 60 in response to the LOAD signalunder the control of the timing controller 30.

The source driver 40 outputs a data line driving signals (D1, D2, . . ., Dm) for driving liquid crystal in the LCD panel 60 to each of the datalines of the LCD panel 60 based on the source driving signal (LOAD,Hstart, RGB signal having the borderline information) outputted from thetiming controller 30.

The gate driver 50 outputs a first dummy line driving signal, gate linedriving signals (G1, G2, . . . , Gn) and a second dummy line signal toeach of the gate lines of the LCD panel 60 based on the gate drivingsignal (gate elk, Vstart) outputted from the timing controller 30. Thefirst dummy line driving signal, the gate line driving signals (G1, G2,. . . , Gn) and the second dummy line signal control turn-on andturn-off of thin film transistors through gate terminals of the thinfilm transistors based on the gate driving signal (gate clk, Vstart).The first dummy line driving signal, gate line driving signals (G1, G2,. . . , Gn) and the second dummy line signal is sequentially applied toeach of the gate lines of the LCD panel 60 by a clock signal or the gateclk. Hereinafter, the first dummy line driving signal, gate line drivingsignals (G1, G2, . . . , Gn) and the second dummy line signal is definedas a gate driving signal. For example, when the LCD panel has arectangular shape of display area, the first and the second dummy linedriving signals drive gate lines of the thin film transistorscorresponding to the top and bottom borderlines, respectively.

The Vstart signal indicates a beginning point of the gate driving signalthat is inputted to the gate lines of the LCD panel 60 from the gatedriver 50.

The LCD panel 60 includes a plurality of gate lines (not shown), aplurality of data lines (not shown) intersecting the gate lines, thinfilm transistors (refer to FIG. 5A and FIG. 6A, etc.), liquid crystalcapacitors (Clc, refer to FIG. 5A) and storage capacitors (Cst).

The thin film transistors are arranged in a matrix shape in a regionthat is surrounded by the gate lines and the data lines, and the thinfilm transistors are connected to the gate lines and the data lines. Theliquid crystal capacitor transmits light in response to a voltage of thedata line driving signal when the thin film transistor is turned on. Thestorage capacitor accumulates data line driving signal (D1, D2, . . . ,Dn) when the thin film transistor is turned on, and applies theaccumulated data line driving signal (D1, D2, . . . , Dn) to the liquidcrystal capacitor when the thin film transistor is turned off.

The driving circuits of the LCD device for displaying the borderline canbe applied not only to the LCD device but also can be applied to otherflat panel display device such as the electroluminescent display deviceby a minor variation of the driving circuit.

FIG. 2 is a view showing a display screen of an LCD panel in which theborderline is being displayed by means of the LCD device of FIG. 1.

Referring to FIG. 2, the display area 200 is divided into a first areaand a second area. The borderlines are formed on the first area. Thesecond area is a remaining area of the display area except the firstarea, and images are displayed on the second area.

The first area includes a first border area 254 a representing a topborderline, a second border area 254 b representing a bottom borderline,a third border area (256-1, 256-2, . . . , 256-n; hereinafter refer to256) representing a left borderline, a fourth border area (258-1, 258-2,. . . , 258-n; hereinafter refer to 258) representing a rightborderline.

The first border area 254 a has a thickness no less than a pixel, andthe thickness of the first border area 254 a can be regulated by a user.For example, a button for regulating the thickness of the first borderarea 254 a may be on an outside of an LCD module. In addition, athickness selection menu, for example an icon, may be displayed on adisplay screen of the LCD device, so that users can select a thicknessof the first border area 254 a by clicking the thickness selection menu.The second, third and fourth border areas (254 b, 256, 258) may have thesame thickness as that of the first border area 254 a or can beregulated to have a thickness different from that of the first borderarea 254 a.

The second area of the display area 200 except the borderlines may becomprised of n lines.

FIG. 3 is a view showing R.G.B. signals applied to the LCD panel so asto display the borderline by means of the LCD device of FIG. 1.

Referring to FIG. 3, the LCD panel 60 receives a first line RGB signal352-1, a second line RGB signal 352-2, . . . , and (n) th line RGBsignal 352-n from the timing controller 30. The first line RGB signal352-1 provides image data displayed on a first line in the second areaof the display area 200, the second line RGB signal 352-2 provides imagedata displayed on a second line in the second area of the display area200, and the (n) th line RGB signal 352-n provides image data displayedon a (n) th line in the second area of the display area 200. The imagedata indicates a data displayed on the display area except a datadisplayed on the borderline.

The timing controller 30 generates a first dummy line signal fordisplaying a borderline on the first border area 254 a and a seconddummy line signal for displaying a borderline on the second border area254 b.

In addition, the timing controller 30 adds dummy pixel signal fordisplaying the borderline on the third border area 256 such as a firstline dummy pixel signal 356-1, a second line dummy pixel signal 356-2, .. . , (n) th line dummy pixel signal 356-n (hereinafter refer to a firstdummy pixel signal 356 for displaying the borderline on the third borderarea 256) to one end of a first line RGB signal 352-1, a second line RGBsignal 352-2, . . . , a (n) th line RGB signal 352-n, respectively.

In addition, the timing controller 30 adds dummy pixel signal fordisplaying the borderline on the fourth border area 258 such as a firstline dummy pixel signal 358-1, a second line dummy pixel signal 358-2, .. . , (n) th line dummy pixel signal 358-n (hereinafter refer to a firstdummy pixel signal 358 for displaying the borderline on the fourthborder area 258) to the other end of the first line RGB signal 352-1,the second line RGB signal 352-2, . . . , the (n) th line RGB signal352-n, respectively.

The timing controller 30 adds the first, second dummy line signal, aplurality of dummy pixel signals for displaying the borderlines to thefirst line RGB signal 352-1, the second line RGB signal 352-2, . . . ,the (n) th line RGB signal 352-n, to thereby display the borderlines onthe LCD panel.

Hereinafter, there is described the process for applying image data tothe LCD panel 60 through a source driver 40 in order to display theborderline.

FIG. 4 is a view showing R.G.B. signals applied to the LCD panel througha source driver so as to display the borderline by means of the LCDdevice of FIG. 1.

Referring to FIG. 4, when a first dummy line driving signal is appliedto each gate line disposed in a first row of the LCD panel 60 from thegate driver 50, signals (354-a-1, 354-a-2, 354-a-3, . . . , 354-a-(m−2),354-a-(m−1), 354-a-m) corresponding to first row signals of the dataline driving signals (D1, D2, . . . , Dm) is outputted to each of the mdata lines corresponding to the first row. Accordingly, the firstborderline is displayed on the display area 70.

Then, when a first gate line driving signal G1 is applied to each gateline disposed in a second row of the LCD panel 60 from the gate driver50, signals (356-1-1, 356-1-2, 356-1-3, . . . , 356-1-(m−1), 356-1-m)corresponding to second row signals of the data line driving signals(D1, D2, . . . , Dm) is outputted to each of the m data linescorresponding to the second row. Accordingly, portions of the third andfourth borderlines, and a first line RGB signal 352-1 is displayed onthe second row of the display area 70.

When a second gate line driving signal G2 is applied to each gate linedisposed in a third row of the LCD panel 60 from the gate driver 50,signals (356-2-1, 356-2-2, 356-2-3, . . . , 356-2-(m−1), 356-2-m)corresponding to third row signals of the data line driving signals (D1,D2, . . . , Dm) is outputted to each of the m data lines correspondingto the third row. Accordingly, portions of the third and fourthborderlines, and a second line RGB signal 352-2 is displayed on thethird row of the display area 70.

According to above method, image data are displayed on a fourth, fifth,. . . , (n−2) th row of the LCD panel. Then, when a (n) th gate linedriving signal Gn is applied to each gate line disposed in a (n+1) throw of the LCD panel 60 from the gate driver 50, signals (356-n-1,356-n-2, 356-n-3, . . . , 356-n-(m−1), 356-n-m) corresponding to (n+1)th row signals of the data line driving signals (D1, D2, . . . , Dm) isoutputted to each of the m data lines corresponding to the (n+1) throw.

Finally, when a second dummy line driving signal is applied to each gateline disposed in a (n+2) th row of the LCD panel 60 from the gate driver50, signals (354-b-1, 354-b-3, 354-b-(m−2), 354-b-(m−1), 354-b-m)corresponding to the (n+2) th row signals of the data line drivingsignals (D1, D2, . . . , Dm) is outputted to each of the in data linescorresponding to the (n+2) th row. Accordingly, the second borderline isdisplayed on the display area 70. Heretobefore, a method for displayingthe borderline by using control signals, such as the dummy line signalsand the dummy pixel signals, of the timing controller 30 used in adriver circuit for driving the LCD panel 60. In the above case, thetiming controller 30 should generate the dummy line signals and thedummy pixel signals in addition to the conventional control signals fordriving the LCD panel 60.

Hereinafter, there is described a method for displaying the borderlineby using color filters and liquid crystal in a normally white mode.

In the normally white mode, all light being incident into the liquidcrystal interposed between a TFT substrate and a color filter substrateis transmitted completely. In order to achieve the normally white mode,electric field should not be formed on the liquid crystal, so that theliquid crystal may transmit all light being incident into the liquidcrystal of the LCD device. In other words, zero electric field is formedon the liquid crystal.

In addition, the borderline having predetermined colors can be displayedby allowing no signals to be transmitted to pixel electrodes of the TFTsubstrate corresponding to the border area in the normally white modewhile color filters are formed on portions of the color filter substratecorresponding to the color filter substrate of the LCD panel 60.

In order that no signals, such as image data, may be transmitted topixels of the TFT substrate corresponding to the border area, forexample, no thin film transistors may be formed on portions of the TFTsubstrate corresponding to the borderline, or the pixel electrodes ofthe TFT substrate corresponding to the borderline may be maintained tobe electrically disconnected with the thin film transistors of the TFTsubstrate corresponding to the borderline.

The normally white mode can be formed when pixels of the TFT substratecorresponding to the border area have failures.

Signals applied to the source electrodes of the thin film transistorscannot be transmitted to the pixels of the TFT substrate correspondingto the border area when patterns, for example gate electrode pattern ofthe thin film transistor, are not formed due to foreign substancegenerated from photolithography process, or when the drain electrode ofthe thin film transistor is not electrically connected to the pixelelectrode through contact hole. The pixel failure may be used so as todisplay the borderline on the LCD panel. Since the borderline can bedisplayed even when pixel failure occurs on the pixels of the TFTsubstrate corresponding to the borderline, the active matrix drivingdisplay device and image displaying method for displaying the borderlinehave strong resistance to process failure in an LCD fabrication process.

FIGS. 5A, 5B and 5C are equivalent circuit diagrams showing a thin filmtransistor corresponding to the borderline of the LCD panel so as todisplay the borderline according to exemplary embodiments of the presentinvention. FIGS. 6A, 6B and 6C are sectional views showing an LCD panelincluding the thin film transistor shown in FIGS. 5A, 5B and 5C.

Referring to FIG. 5A and FIG. 6A, a gate line formed on the LCD panel 60is connected to a gate electrode of the thin film transistor, and a dataline is connected to a source electrode of the thin film transistor.

One end of the liquid crystal layer 120 is contacted to drain electrodes108 of the thin film transistors that are electrically connected to thepixel electrode 112, and the other end of the liquid crystal layer 120is contacted to a common electrode 176 of the color filter substrate170, to thereby complete the liquid crystal capacitor (Clc). The liquidcrystal capacitor transmits light in response to a voltage of the dataline driving signal inputted through the drain electrode 108 when thethin film transistor is turned on.

The storage capacitor is connected to the liquid crystal capacitor inparallel, accumulates data line driving signal (D1, D2, . . . , Dn) whenthe thin film transistor is turned on, and applies the accumulated dataline driving signal (D1, D2, . . . , Dn) to the liquid crystal capacitorwhen the thin film transistor is turned off.

As shown in FIG. 6A, the gate electrode 106 is formed on a channel layer104 of the TFT substrate, the drain electrode 108 and the sourceelectrode 102 is formed on the gate electrode 106. The source electrode102 is electrically connected to the drain electrode 108 through thechannel layer 104. The pixel electrode 112 is formed after the drainelectrode 108 is formed, and a portion of the pixel electrode 112 iselectrically connected to the drain electrode 108.

Color filters 174 are formed on a transparent substrate 172 of the colorfilter substrate 170 so as to be opposite to the pixel electrode 112,and the common electrode 174 is formed on the color filters 174. Thedata line driving signal inputted through the source driver 40 isapplied to pixel electrode 112 through the source electrode 102 and thedrain electrode 108. While a predetermined voltage is applied to thecommon electrode 176, each of the liquid crystal molecules in the liquidcrystal layer 120 is rearranged according to a direction of the electricfield formed between the common electrode 176 and the pixel electrode112. The amount of light that transmits the liquid crystal layer dependson the intensity of the electric field because a degree of therearrangement of the liquid crystal molecules varies according to theintensity of the electric field. The light that transmits the liquidcrystal layer 120 passes through the color filters 174, and displayscolor corresponding to the RGB color of the color filters 174.

In order that no signals, such as image data, may be transmitted topixels of the TFT substrate corresponding to the border area, forexample, the thin film transistors 114 of the pixels corresponding tothe borderline may be maintained to be electrically disconnected withthe pixel electrodes of the pixels corresponding to the borderline.

According to a first method, the gate electrode of the thin filmtransistor of the pixel corresponding to the border area may be notconnected to the gate line, but be connected to the ground. Accordingly,the thin film transistor 114 is turned off, and the image data outputtedfrom the data line is not transmitted to the pixel electrode 112. Inaddition, the pixel electrode 112 is electrically connected to thecommon electrode 176 so as to maintain the electric potential differencebetween the pixel electrode 112 and the common electrode 176 to be zero.Thus, the normally white mode can be maintained, and the light thattransmits the liquid crystal passes through the color filter 174 formedon the color filter substrate 170, to thereby display the borderlinehaving a predetermined color determined by the color filter 174.

According to a second method, as shown in FIG. 5B, the potentialdifference between the pixel electrode 112 and the common electrode 176is maintained to be zero, and the drain electrode of the thin filmtransistor 114 of the pixel corresponding to the borderline ismaintained to be open circuit. Thus, since the image data outputted fromthe data line is not transmitted to the pixel electrode 112, the lightthat transmits the liquid crystal in the normally white mode passesthrough the color filter 174 formed on the color filter substrate 170,to thereby display the borderline having a predetermined colordetermined by the color filter 174.

FIG. 6B is a sectional view showing the LCD panel 60 when the drainelectrode of the thin film transistor 114 of the pixel corresponding tothe borderline is maintained to be open circuit.

Referring to FIG. 6B, the pixel electrode 112 is not electricallyconnected to the drain electrode 108 so as to maintain the drainelectrode of the thin film transistor 114 to be open circuit.

According to a third method, as shown in FIG. 5C, the potentialdifference between the pixel electrode 112 and the common electrode 176is maintained to be zero, and the thin film transistor of the pixelcorresponding to the borderline is not formed on the TFT substrate 110.Thus, since the image data outputted from the data line is nottransmitted to the pixel electrode 112, the light that transmits theliquid crystal in the normally white mode passes through the colorfilter 174 formed on the color filter substrate 170, to thereby displaythe borderline having a predetermined color determined by the colorfilter 174.

FIG. 6C is a sectional view showing the LCD panel 60 when the thin filmtransistor 114 of the pixel corresponding to the borderline is notformed on the TFT substrate 110. In addition, the pixel electrode 112also may be not formed on the TFT substrate 110. On the other hand,while the thin film transistor 114 of the pixel corresponding to theborderline is formed on the TFT substrate 110, the pixel electrode 112is not formed on the TFT substrate 110, to thereby display theborderline having a predetermined color determined by the color filter174.

According to a third method, the common electrode 176 is not formed onportions of the color filter substrate 170 corresponding to theborderline by using another photo mask. Thus, when electric field is notformed on the liquid crystal disposed on portions corresponding to theborder area, it is possible to display the borderline having apredetermined color.

FIG. 7 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a firstexemplary embodiment of the present invention.

Referring to FIG. 7, blue (B) color filter is formed on portions (B1,B1′) of the color filter substrate 170 corresponding to the border areaso as to display a borderline having a blue color. As shown in FIG. 7,the borderline can be displayed by using one layer of color filters.

According to above mentioned method, when signals, such as image data,are not applied to the pixels disposed on portions of the TFT substrate110 corresponding to the border area, the light that transmits theliquid crystal disposed on portions corresponding to the border areapasses through the blue color filter (B), to thereby display theborderline having blue color.

FIG. 8 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a secondexemplary embodiment of the present invention, FIG. 9 is a schematicview showing an LCD panel on which color filters are formed so as todisplay the borderline according to a third exemplary embodiment of thepresent invention.

Referring to FIG. 8, red (R), green (G) and blue (B) color filters areformed on portions (B1, B1′) of the color filter substrate 170corresponding to the border area so as to display a borderline having apredetermined color. As shown in FIG. 8, for example, the borderlinehaving a white color can be displayed by using one layer of color filterthat is alternatively arranged on portions (B1, B1′) of the color filtersubstrate.

On the other hand, as shown in FIG. 9, the thickness (T1, T2, T3) ofeach of the color filters can be the same, or different from each other.In other words, a borderline having desired color(s) can be formed byvarying the thickness of the color filter. The thickness of the colorfilter can be regulated by varying a coating thickness of the colorfilter during spin coating process or coating process using a slitcoater. The thickness of the color filter can be regulated through slitexposure process using a slit mask.

In other words, according to above mentioned method, when no signals,such as image data, is not transmitted to the pixels disposed onportions of the substrate 110 corresponding to border area in thenormally white mode, the light that transmits the liquid crystaldisposed on portions corresponding to the border area passes through theR, G, B color filters, to thereby display a borderline having a whitecolor or the other colors.

FIG. 10 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a fourthexemplary embodiments of the present invention.

Referring to FIG. 10, two layers of red (R) and blue (B) color filtersare formed on portions (B1, B1′) of the color filter substrate 170corresponding to the border area so as to display a borderline having apredetermined color. As shown in FIG. 10, the borderline having apredetermined color can be displayed by using two layers of colorfilters.

When two layers of color filters are used, the thickness (T1, T2) ofeach of the color filters can be the same, or different from each other.

FIG. 11 is a schematic view showing an LCD panel on which color filtersare formed so as to display the borderline according to a fifthexemplary embodiments of the present invention.

Referring to FIG. 11, three layers of color filters are formed onportions (B1, B1′) of the color filter substrate 170 corresponding tothe border area so as to display a borderline having two colors. Asshown in FIG. 8, for example, the borderline having two colors can bedisplayed by using two layers of color filters. The thickness (T1, T2,T3) of each of the color filters can be the same, or different from eachother. As shown in FIG. 11, for example, a borderline having two colorsexcept red color can be formed by varying the thickness of red (R) colorfilters and the thickness of other color filters. The borderline havingtwo colors can be displayed by means of one layer of color filters ortwo layers of color filters.

Although above preferred exemplary embodiments discuss the liquidcrystal display device, the method for displaying the borderline couldalso be applied to the flat panel display device such as theelectroluminescent display device, the plasma display panel and fieldemission display device.

This invention has been described with reference to the exemplaryembodiments. It is evident, however, that many alternative modificationsand variations will be apparent to those having skill in the art inlight of the foregoing description. Accordingly, the present inventionembraces all such alternative modifications and variations as fallwithin the spirit and scope of the appended claims.

The invention claimed is:
 1. A liquid crystal display device comprising:a first substrate; a second substrate being opposite to the firstsubstrate; a first color filter formed on a first portion of the secondsubstrate, the first portion corresponding to a first area of a displayarea, the first area being a border area of the display area; a secondcolor filter formed on a second portion of the second substrate, thesecond portion corresponding to a second area of the display area, thesecond area being the display area enclosed by the border area; a firstliquid crystal layer disposed between the first and the second substratein the first area, and a zero electric field being formed on the firstliquid crystal layer; a second liquid crystal layer disposed between thefirst and the second substrate in the second area; a plurality of thinfilm transistors formed on a third portion of the first substrate, thethird portion corresponding to the first area; a plurality of firstpixel electrode being arranged in a matrix shape on a fourth portion ofthe first substrate, the fourth portion corresponding to the first area,the first pixel electrodes physically disconnected to electrodes of thethin film transistors to which an image signal is applied; and a commonelectrode formed on the first and the second color filter, wherein thezero electric field is formed by nullifying an electric potentialdifference in the first liquid crystal layer.
 2. A liquid crystaldisplay device comprising: a first substrate; a second substrate beingopposite to the first substrate; a first color filter formed on a firstportion of the second substrate, the first portion corresponding to afirst area of a display area, the first area being a border area of thedisplay area; a second color filter formed on a second portion of thesecond substrate, the second portion corresponding to a second area ofthe display area, the second area being the display area enclosed by theborder area, wherein an electric field is formed in the second areahaving a plurality of thin film transistors and the plurality of thinfilm transistors applies an image signal to the second area; a firstliquid crystal layer disposed between the first and the second substratein the first area, and a zero electric field being formed on the firstliquid crystal layer; a second liquid crystal layer disposed between thefirst and the second substrate in the second area, wherein the firstcolor filter comprises three layers, and the three layers has a samethickness, and wherein the zero electric field is formed in the firstarea by excluding any thin film transistors from the first area.
 3. Aliquid crystal display device comprising: a first substrate; a secondsubstrate being opposite to the first substrate; a first color filterformed on a first portion of the second substrate, the first portioncorresponding to a first area of a display area, the first area being aborder area of the display area; a second color filter formed on asecond portion of the second substrate, the second portion correspondingto a second area of the display area, the second area being the displayarea enclosed by the border area, wherein an electric field is formed inthe second area having a plurality of thin film transistors and theplurality of thin film transistors applies an image signal to the secondarea; a first liquid crystal layer disposed between the first and thesecond substrate in the first area, and a zero electric field beingformed on the first liquid crystal layer; a second liquid crystal layerdisposed between the first and the second substrate in the second area,wherein the first color filter is a single layer, and wherein the zeroelectric field is formed in the first area by excluding any thin filmtransistors from the first area.